Consumers have used cosmetic products to care for their skin since the dawn of civilization. These products have ranged from simple, commonly-available materials such as honey and plant extracts to, in recent years, hi-tech synthetic ingredients in a wide variety and array of product forms.
Numerous compounds have been described in the art as being useful for regulating skin condition, including regulating fine lines, wrinkles and other forms of uneven or rough surface texture associated with aged or photodamaged skin. However, many materials require multiple applications over an extended period to provide such appearance benefits. It would be advantageous to provide a topical composition which provides a more immediate improvement in the appearance of fine lines, wrinkles, pores and other forms of undesirable skin surface texture.
One approach has been to incorporate particulate materials, such as TiO.sub.2, into skin care compositions. For example, emulsions may contain TiO2 as an opacifying agent to provide a white appearance to the emulsion. Commercial sunscreening compositions may employ such particulates to impart a sunscreening effect. Several publications have also disclosed the use of TiO.sub.2 in skin care compositions. See, e.g., U.S. Pat. No. 5,223,559 and patent application Nos. DE 245815, WO 94/09756 and JP 08188723. In addition, R. Emmert has stated the desire to use optical means to formulate products that give the consumer an immediate, visual improvement (Dr. Ralf Emmert, Quantification of the Soft-Focus Effect, Cosmetics & Toiletries, Vol. III, July 1996, pp. 57-61). Emmert discloses that one can mechanically fill in skin lines with a reflective substance such as TiO.sub.2. However, Emmert teaches that such reflective materials result in an undesirable mask-like appearance, and that one should therefore use a material that diffuses light yet is sufficiently transparent to avoid the mask-like appearance.
Known topical compositions containing reflective materials such as TiO.sub.2, generally either do not provide coverage sufficient to reduce the appearance of skin imperfections, or tend to result in unacceptable skin whitening or other unnatural appearance when applied to the skin. It has also now been found that materials which primarily diffuse light, rather than reflect light, do not provide good coverage of skin imperfections when used in amounts which are aesthetically acceptable to consumers. More particularly, when used at relatively high concentrations to provide coverage, these materials suffer from unacceptable skin whitening.
Additionally, reflective particulate materials, such as TiO.sub.2, tend to feel dry and add to the negative perception that the composition is not being absorbed into the skin and/or that the composition is not providing a skin conditioning benefit. As a result, relatively high concentrations contribute to amplify these negative qualities. It has also been found that reflective particulate materials tend to agglomerate, e.g., cluster together. When these materials agglomerate greater amounts of particulate materials are required to provide sufficient coverage, which also adds to the negative perceptions. Thus, it would be desirable to realize aesthetically acceptable degrees of skin coverage even though relatively low concentrations of TiO.sub.2 are used.
In addition, it is desirable for cosmetic compositions to have good aesthetics during application onto the skin and while on the skin. Good aesthetics means that the composition (i) is light and nongreasy, (ii) has a smooth, silky feel upon the skin, (iii) spreads easily, and (iv) absorbs quickly. These desirable aesthetics are often achieved by incorporating thickening agents into a composition. However, it is known that particulate materials, such as metal oxides, are often not compatible with many thickening agents, such as carboxylic acid polymers, and skin care actives.
The present invention overcomes the problems discussed hereinbefore (e.g., unacceptable skin whitening, aesthetics, and formulation compatibility issues) by employing charged, surface-treated, reflective particulate materials which are dispersed in a thickened hydrophilic carrier. Surface treated particulates are known in the cosmetic industry, however, their use heretofore has been typically limited to non-aqueous phases and anhydrous-based products such as lipsticks, powders, mascaras, and to heavy, oil-based emulsions. It has been found in the present invention that charged, surface treated reflective particulates (i) are compatible with polymeric thickeners, such as carboxylic acid polymers, (ii) can provide acceptable degrees of skin coverage at relatively low concentrations, and (iii) can be formulated into compositions having excellent aesthetics. Such compositions are especially suitable for providing an immediate visual improvement in skin appearance when topically applied.
In light of the foregoing, it is an object of the present invention to provide topical compositions suitable for imparting an immediate visual improvement in skin appearance.
It is another object of the present invention to provide topical compositions containing a reflective particulate material, e.g., TiO.sub.2, which provides desirable coverage of skin imperfections such as pores and uneven skin tone, while maintaining a natural skin appearance (e.g., without unacceptable skin whitening).
It is another object of the present invention to provide topical compositions which provide especially effective skin coverage while using relatively small amounts of reflective particulate material.
It is yet another object of the present invention is to provide such topical compositions which are additionally useful for regulating skin appearance and/or condition, especially regulating textural or tonal discontinuities in skin (e.g., pores and uneven skin color).
Another object of the present invention is to provide topical composition that utilize reflective particulate materials which are compatible with other composition components such as, actives and polymeric thickeners.
It is yet another object of the present invention to provide methods of improving skin appearance and/or condition by topical application of the skin care compositions described herein.